Oven

ABSTRACT

An energy absorbing oven construction wherein the oven is constructed of heat transfer resistant panel members bolted together by exterior frame members and wherein the roof of the oven is unattached such that in the event of an oven blowout the roof panels will lift off without causing disintegration of the oven itself. Burner elements within the oven are placed adjacent a spiral conveyor carrying products to be baked within the oven and the temperature of the burner elements is controlled in such a manner so that uniform heating of the products as they are carried through the oven by the spiral conveyor is maintained.

United States Patent Inventors William E. Lanham;

Gene C. Miller; William E. Lanham, Jr., all of Decatur, Ga. [21] Appl.No. 773,855 [22] Filed Nov. 6, 1968 [45] Patented June 29, 1971 [73]Assignee Lanharn Machinery Co., Inc.

Atlanta, Ga.

[54] OVEN 5 Claims,4 Drawlng Figs.

[52] US. Cl 107/57, 107/54 [511 lnt.Cl AZlb H42 [50] Field of Search107/57, 55, 55.5; 34/189, 190

[56] References Cited UNITED STATES PATENTS 990.003 4/1911 Piper 107/57(3) 1,073,126 9/1913 Hitchcock 107/57 (3) 1,938,294 12/1933 Lauterbur etal. 107/57 (3) 1,949,684 3/1934 Houlis 107/57 Primary E.raminer- LouisK. Rimrodit Ar1orney-Curtis, Morris and Safford.

ABSTRACT: An energy absorbing oven construction wherein the oven isconstructed of heat transfer resistant panel members bolted together byexterior frame members and wherein the roof of the oven is unattachedsuch that in the event of an oven blowout the roof panels will lift offwithout causing disin tegration of the oven itself. Burner elementswithin the oven are placed adjacent a spiral conveyor carrying productsto be baked within the oven and the temperature of the burner elementsis controlled in such a manner so that uniform heating of the productsas they are carried through the oven by the spiral conveyor ismaintained.

PATENTEnJummn 3,589,307

SHEET 1 0F 2 Fig.|

INVENTOR. William E.Lanhom BY Gene C. Muller William E. Lonhom,Jr.Zuni/s, MOIIRIP flfinb AT TORNEYS PATENTEU JUN28 I971 SHEET 2 [IF 2Fig.3

zeofi 21 I268 260 INVENTOR.

William E. LGnhOm Gene C. Miller William E. Lonhom, Jr.

flax/Li Mica.

ATTORNEYS OVEN This invention relates to ovens and more in particular toovens for bakery products which are carried continuously through theoven .structure, for example on an endless spiral conveyor therethrough.

An object of this invention is to provide an improved oven for bakeryproducts. A further object of this invention is to provide an ovenconstruction for baked products wherein damage to the oven due toblowout is minimized. A further object of this invention is to providean oven construction hav ing a burner arrangement for carefullycontrolling oven heat in order to uniformly bake products such as bakerygoods in an economical and commercial manner. A still further object ofthe present invention is to provide an oven for use with a spiralconveyor system to carry bakery products therethrough wherein the bakedproducts are subjected to uniform and carefully controlled oven heat.

In the drawings:

FIG. 1 is a partial perspective view of an oven constructed according tothe present invention;

HO. 2 is a vertical section through the oven of the present inventionshowing the spiral conveyor therein;

FIG. 3 is a horizontal section through a portion of the oven; and

FIG. 4 is a vertical section of the lower portion of the oven.

The oven of the present invention has been designed for use with acontinuous proof and bake system for bakery products as disclosed incopending application U.S. Ser. No. 627,700, filed Apr. 3, 1967, nowU.S. Pat. No. 3,478,705, granted Nov. 18, 1969, which application isincorporated herein by reference. In that application, a continuoussystem for proof ing and baking bakery products was disclosed wherein acontinuous conveyor system is shown which spirals within a proofingenclosure to proof the baked products, and then through an ovenenclosure to bake the baked products. Passage of the products throughthe oven is on trays supported on the conveyor which spirals, forexample, downwardly through the oven so that each product passes throughthe same zone of the oven as every other product and hence is subjectedto uniform baking conditions.

Reference is now made to FIGS. 1,3 and 4 for details of the ovenconstruction. Oven 100 is constructed from a number of individual panelelements 258 which comprise two opposed facing sheets 260 of a fire andheat resistant material, such as Marinite, separated by a plurality ofshort channel sections 262 at the top and bottom of each sheet. An endpanel element 258, used at a corner of the oven, also includes a channelelement 264 which extends the length of sheets 260. The sheets 260 ofMarinite are secured to the channel sections 262 and the channel element264 in any suitable manner, i.e., by bolts or barbed skewers. The spacebetween the panel sheets is filled with an insulating material 266, suchas batts of mineral wool or rock wool, in order to provide an oven panelthat is highly resistant to heat transfer from the hot interior of theoven to the cool exterior.

The supporting structural framework for the oven is positioned on theexterior surface and includes upstanding structural members 268 at thejunction of adjacent panels 258. The panels 258 are supported and heldin contiguous relationship by means of a fastening member such as a bolt270 passing through the upstanding support 268. spacer plate 272, cutoutportions (not shown) in the edge of the sheets 260, interior spacerplate 274 and held by a retaining nut 276. Cross brace members 278extend between upstanding members 268 and corner brace members 280. Theoven framework is thus completely on the exterior surface and there isno necessity for any structural members within the oven itself exceptthat structure necessary to support the burner elements and a productconveying system within the oven.

Roof panel elements 282 constructed in the same manner as side panelelements 258 are positioned to rest freely on the oven top in order toprovide blowout protection. Thus, if an accidental explosion or blowoutoccurs within the oven, the roof panels 282, since they rest freely onthe top surface of the oven, will blow away from the oven affording ameans for pressure release so that the oven will not be unduly damagedas a result of the explosion. The roof panel elements 282 rest on top ofcross beam members 288 which are supported on opposite upstandingmembers 268. l-beams 286 fixed to cross beams 284 add rigidity to theoven structure as well as bridging the gap between adjacent top panelmembers 282. End cover plates 288 cover the open ends of the I-beams toprovide a smooth continuous appearance to the oven structure. Theexterior surface of the various oven panels are covered with adecorative panel material 290 which may be for example porcelain steelpanels or fiberglass.

Referring now to FIG. 2, there is shown an arrangement for a conveyorsystem which spirals within the oven and burners in the oven 100. Inthis arrangement, burner elements 15a are disposed in pairslongitudinally to the straight length of conveyors 9 within the oven.The burners 15a are of the gas-fired type and are ignited by ignitionelectrodes 250 extending into the oven. The burners are provided withautomatic temperature controls and can be individually controlled andare responsive to temperature sensing devices shown diagrammatically as17 in FIG. 2 so as to provide optimum oven heat. The temperature sensingdevices 17 are associated with each burner 15a and are suitablysupported within the oven enclosure. Since the conveyors carrying theproducts to be baked pass directly over the zone of oven heat, the zoneof heating can be precisely controlled to provide a uniform baking.Further, since each product passes through the same heating condition asall of the other products, the result is a uniform baking for all of theproducts and thus the quality and uniformity of the baked products canbe precisely controlled.

The precise temperature control afforded by the individually controlledtemperature responsive burner units and the concentrated heating zones,due to the position of the burners parallel to and directly under themajor length of the conveyor in the oven, eliminate the problemsattendant to oven spring," e.g., killing off the yeast and giving thebread the final proofing to the final product size. Heretofore, steamhas been injected into the oven before the product, or heat absorbershave been sent in before the product to eliminate flash heat and coolthe ovens when the heating zones become too hot. With the presentarrangement, the heating zones can be precisely controlled and thereforethe oven spring can also be controlled to produce products to uniformsize without resorting to inexact methods that vary from product run toproduct run.

Ovens incorporating the present invention provide very precise controlupon the baking of the bread products. The attempts at obtaining auniform distribution of heat within prior types of ovens has notproduced completely uniform conditions for the various items. With suchovens, the positions of the products or items upon a tray or upon a rackmay cause them to be maintained at different temperatures or humidity,one being satisfactory and the other not, or neither being satisfactory.With the arrangement of the present invention the conveyor permitsmaintaining uniform circulation of the air so that the position of anitem transversely is not significant from that standpoint. Also, eachitem moves from the top level to the bottom level in the oven and alsothroughout the entire spiral path, so that all of the product items passthrough the same zones. Hence, if the conditions in one zone vary fromthose in another, each item is still given a uniform treatment. Withsome prior ovens, the construction and operation were such that it isnot possible to maintain the desired heating conditions uniformly in theoven without causing resultant damage of the products. The presentarrangement avoids the difficulty, the burner elements are individuallycontrolled in response to temperature sensing devices and, hence, createclosely controlled heating zones through which the products pass. Withprior ovens some attempts to obtain maximum production have resulted inan objectionably high percentage of inferior products. With the presentinvention, the optimum operating conditions for each type of product maybe determined, and the operation can then be accurately carried on.

We claim:

1. In an oven for baking products, the combination of, an oven enclosureand a conveyor for conveying products to be baked through said oven,said conveyor comprising a conveyor run which spirals within said ovenenclosure, said oven including a plurality of heating elements disposedwithin said oven and located parallel to and directly beneath selectedruns of said spiral conveyor and within said oven enclosure thereby tocreate zones of oven heat through which products conveyed by saidconveyor pass and wherein each of said products to be baked is conveyedthrough the same path so that individual products are subjected toidentical heating conditions during passage through said oven.

2. The oven as defined in claim 1 wherein said heating elements areindividually and automatically controlled in response to temperaturesensing devices in said oven and are disposed adjacent said convey pathto closely control the zones of uniform heat so that the uniformity ofthe baked products can be precisely maintained.

3. The oven as defined in claim 1 wherein said oven is comprised ofindividual panel elements having a high resistance to heat transfer,said panels being maintained in a contiguous relation to form an ovenenclosure by means of an exterior supporting structure, said panelscomprising sheets of fire resistant material spaced from each other andhaving insulating material between said sheets.

4. In an oven for baking products in which a spiral conveyor is providedfor carrying the products through the oven, a path of travel for theconveyor through which each of the individual products pass for uniformtreatment in the oven, a plurality of heating elements disposed withinthe oven directly beneath the path of travel of selected runsof saidspiral conveyor to create heating zones in the oven wherein the productsare heated by the direct action of the heating elements, individualtemperature sensing means in each of said zones for automaticallycontrolling the heating elements in the respective zones in response totemperature conditions therein, said sensing means being locatedadjacent the path of travel of said conveyor through their respectivezones to closely control the temperature conditions in said zoneswhereby uniformity of the baked products is maintained.

5. The oven as defined in claim 4 wherein said oven is comprised ofindividual panel elements having a high resistance to heat transfer,said panels being maintained in a contiguous relation to form an ovenenclosure by means of an exterior supporting structure, said panelscomprising sheets of fire resistant material spaced from each other andhaving insulating material between said sheets.

1. In an oven for baking products, the combination of, an oven enclosureand a conveyor for conveying products to be baked through said oven,said conveyor comprising a conveyor run which spirals within said ovenenclosure, said oven including a plurality of heating elements disposedwithin said oven and located parallel to and directly beneath selectedruns of said spiral conveyor and within said oven enclosure thereby tocreate zones of oven heat through which products conveyed by saidconveyor pass and wherein each of said products to be baked is conveyedthrough the same path so that individual products are subjected toidentical heating conditions during passage through said oven.
 2. Theoven as defined in claim 1 wherein said heating elements areindividually and automatically controlled in response to temperaturesensing devices in said oven and are disposed adjacent said convey pathto closely control the zones of uniform heat so that the uniformity ofthe baked products can be precisely maintained.
 3. The oven as definedin claim 1 wherein said oven is comprised of individual panel elementshaving a high resistance to heat transfer, said panels being maintainedin a contiguous relation to form an oven enclosure by means of anexterior supporting structure, said panels comprising sheets of fireresistant material spaced from each other and having insulating materialbetween said sheets.
 4. In an oven for baking products in which a spiralconveyor is provided for carrying the products through the oven, a pathof travel for the conveyor through which each of the individual productspass for uniform treatment in the oven, a plurality of heating elementsdisposed within the oven directly beneath the path of travel of selectedruns of said spiral conveyor to create heating zones in the oven whereinthe products are heated by the direct action of the heating elements,individual temperature sensing means in each of said zones forautomatically controlling the heating elements in the respective zonesin response to temperature conditions therein, said sensing means beinglocated adjacent the path of travel of said conveyor through theirrespective zones to closely coNtrol the temperature conditions in saidzones whereby uniformity of the baked products is maintained.
 5. Theoven as defined in claim 4 wherein said oven is comprised of individualpanel elements having a high resistance to heat transfer, said panelsbeing maintained in a contiguous relation to form an oven enclosure bymeans of an exterior supporting structure, said panels comprising sheetsof fire resistant material spaced from each other and having insulatingmaterial between said sheets.